Air-bypass or surge control for supercharged internal-combustion engines



Apnl 28, 1953 A. BUCHI 2,636,341

AIR-BYPASS OR SURGE CONTROL FORSUPERCHARGED INTERNAL-COMBUSTION ENGINES Filed March 5, 1947 2 SHEETS-SHEET 1 FIG! VENTOR.

Apnl 28, 1953 A. BUCHI 2,636,341

AIR-BYPASS OR SURGE CONTROL FOR SUPERCHARGED INTERNAL-COMBUSTION ENGINES Filed March 5, 1947 2 SHEETSSI-IEET 2 Ill charging blowers.

Patented Apr. 28, 1953 2,636,31 F F ICE AIR-BYPASS OR SURGE CONTROL FOR SUPERCHARGED INTERNAL-COMBUS- TION ENGINES Alfred Biichi, Winterthur, Switzerland Application March 5, 1947, Serial No. 732,640 In Switzerland March 12, 1946 Claims.

My present invention relates to improvements in surge-preventing arrangements on supercharged internal combustion engines comprising a plurality of charging blowers, of the centrifugal and/or axial type, at least one thereof being driven by the engine exhaust gases. Such engines are of the type in which the charging blowers-in accordance with the state of operation of the engine-are cut in or out relative to the air supply, so that at least one thereof delivers directly into the engine.

The subject matter of my present invention consists in control gears, riggings or arrangements adapted to preventat any given pipin connection of the blower delivery lines with the enginethe occurrence of irregularities (such as surging) in the delivery of at least one of the Such controls, which, for example, may comprise devices for blowing off part of the pressure fluid delivered by the respective blower into a space of lower pressure or othe devices serving for the same purpose, may be adjusted either directly by means of the en ine governor or by means of the pressure of a pressure fluid supplied by the engine, such as the exhaust gases, the charging air or the lubricating oil and the like. Such controls also, however, may be operated in common in engines comprising elements (adjustable automatically or from the outside) for piping the output from different kinds of charging blowers directly to the engine or to the other kind of blower.

In the explanation which follows, I assume that the reader is familiar with charging devices for internal combustion engines such as are the subject of my Patent No. 2,296,268, issued September 22, 1942.

Several forms of invention are shown, by way of example, in the accompanying drawings, in

which Fig. 1 shows a side elevation of a motor, partly in section through a control rigging,

Fig. 2 is a front view of the motor of Fig. 1, and

Figs. 3-5 illustrate other forms in partial sections and partly in elevation.

The internal combustion engine I in Figs. 1 and 2 possesses six cylinders 2"l, a governor 8, and

two charging blowers 9 and I0. Blowers 9 and H! are shown in the drawings as being of the radial type. However, it will readily occur to any person skilled in the art that other types of similarly acting blowers could be substituted for the radial blowers here shown. Power to drive blower 9 may be supplied by the engine crankshaft, as

rigging M, i5, opens the circular valve It, thus opening the delivery space I! of blower 9 to the air-intake structure it by way of duct 29. Blower 9 is surging when it is of relatively large capacity, and when the exhaust-turbine driven blower I!) is sucking little or no air. Such latter case, again, may arise upon starting the engine or at low load and/or low speed, in spite of valve 23 being open. The entrance chamber for the charging air to engine I is designated by 231.

Lever i5 may be connected to valve rod l9. either fastly or (as shown in Fig. 1) loosely, so that the latter is actuated by rod I4 only for opening valve 16, in that, when governor 8 with engine I idlingis slowed, rod I4 is pushed to the right. Governor 8, therefore, i not instrumental in closing valve 15. When governor rod Hlwith the load on engine l increasingmoves to the left valve Iii automatically is closed again by the spring 2|, acting against the spring 20.

A handle 22 may be provided on lever l 5 to permit, when required, of holding open or closing circular valve 16 independently of governor 8. In the form of invention according to Fig. 3, a circular valve i6 is so built into the delivery line 25 of the exhaust-turbine driven blower iii as to permit of establishing communication between delivery line 24 and suction line 25 of blower l8. Valve 16 here again (as in Fig. 1) is actuated by governor 8 by way of rigging 14', I5, and comprises a guide stem l9, a helical spring 2| tendmg to push valve 86 to the left into closing position, and a helical spring 253' tending to push valve i6 to the right into open position. Spring disc 2Eiis adjustably mounted on stem E9 to permit of adjusting the tension of springs 2E and 2 l Valve 16' is opened-in accordance with my present invention-when, as seen from Fig. 3, delivery line 24 of blower iii to entrance chamber 231 is closed by the valve 2?, as shown, but engine I and thus also exhaust turbo-blower IU/ i, having been started already, is not capable yet of building up sumcient pressure to open valve 21. if bypass valve It were not opened at this stage of operation, blower 10 would be subjected to surges, which condition will be prevented by means of my present invention.

Fig. 4 shows a form of invention, wherein the bypass valve [6" is actuated by means of a piston 28" secured to valve stem l9". Piston 28 is pushed to the left, biased by a pressure fluid (charging air, exhaust gases, lubricating oil and the like). Valve l6" thus is opened and at least part of the air in delivery space ll may escape through duct 29 into air-intake l8" of blower 9. A wing nut 26" is mounted on the outer end of stem l9", and is pushed by a spring 2!" to the right, i. c. said spring tends to close valve l5".

7 The pressure fluid is supplied through the circular-valve 39 into the cylindrical space 3|. In Fig. i, valve 30" is shown in a position in which the pressure fluid is permitted to flow 3 from 32 into space 3!, and which corresponds to the position of lever l shown in full lines.

Lever l 5" is set, e. g., by a governordnot shown-l by means of the rod l4".

In the position of lever l5" shown by dotted lines, the admission of pressure fluid-at-32 is closed, and cylinder space M is drainedthrou'gh the aperture 33". The pressure-"bf -sprmg-* z'l':' then closes valve l8".

Fig. 1.

Fig. '5 shows a-form: of invent-ion; wherein the valves 16" and Hi are directlyconnected'with valves 23and =2'ixrespectively. The latter-close independently of each other,- inthat :they are automatically opened or closed when a 'higher pressure exists in the engine "entrance-chamber 231 than blowers il and W respectively are capable of building up in their stateof 'operation. The arrangement, i-further, may be-such-.-that the valve 56 is opened "when valvew23 also isopened; Valves 16" -'and--2-3 -alsd-mayrclose approximately at-the same time; Such-may be the case, when the engine is started, -or when it is running under low'load.

Valve Z'hhowever, is closed, when valve 18"" isopen, so that the air theniis bypassedirom the delivery chamber M into the suction chamber 25of-thesame-blower ill. Valves 2%, it? and 21, .lfi respectively, *fll'EebiBfiEd into certain desired positions bythe-springs 2W", 21 and 2M" respectively. Thewing nuts 26 and 28"" permit adjusting the spring actions. The elements Hi'; 46'1" :maybe spaced-as de sired from 'valves- -23,-' 2l :respectivelyontheir common s spindles. -'A closure .-plate *2 5a is placed over the horizontal-end of-the turbo-blower entrance pipe section =25:

Arrangements according to Fig. 5 "are capable of operating all togetherautomaticallyat all operating stages of engine *I They? cut the delivery lines 'of the blowers in and out :properly, and 'at the "same time prevent the occurrence of the phenomenonofs'urging in the kinds of charging blowers used:

The latter is opened'again' in the same way as described in connection-with Wherever the term findependently driven is employed to describe"-blower oriblowers in the claims, :I intend to'comprehend a *blower or blowers which? are :not driven by :anwexhaust gas turbine, but-rather, by. gearing with theengine shaft, or by som'e otherpowerrotatingsunitrsuch driven by the 'exh'au'stigases of the engine to supply air under pressure EtO 'thQ air: intake chamber of the engineaantauxi-liary independently driven blower-to supply airto said chamber, a first valve in the line betweenthe auxiliary :blowerandthe chamber closedrin *l'espo'nse' to :pressure inthe chamber at 'high turbo 'blowerspeedsto --direct the air from::ther-auxiliary blower to the intake side of the turboebloweni'a second valve between the turbo blower and the chambenadaptedto close off thetmhd blowerntrom. the chamberat low turbo blower speeds, the bombination there.- with "of controlsmeansa tol prevent surging in each blower, comprising a bypassing "valveuto permit escape chair-behind the auxiliary blower 7 into the atmosphere, a relief-valve in thedelivery line of the turbo blower, .s'aidvielietvalve leading back .toz'therintake side? of.:th'e- ;turbo-blower, means connecting the said first valve to the :saidblower.

b'y-passing valve to open niatmsesnd by passing "-valve simultaneously with the opening and clos- -ing-.-of said first valve, and means connecting the "the "closing "of the second valve whereby at a pi e'deteit'n'i'ned. "pressure in the turbo blower 'line tothe-air intake chamber said second valveis closed and the relief valve leading to the intake side of the turbo blower is simultaneously-op ened, andfull operationoi said turbo blower results in theopening of said second valveand the closingof said relief valve, and with= the building up of press u're in the air intake chamber-there results further a closing of said fir-st valve and a simultaneous closing of the bypassing valve-behind the auxiliary blower to stoptheescapeot-any pressure into the atmosphere;

2. The combination as described in claim 1 wherein adjustable spring means are provided to oppose-the'opening of at least one of said first and second valves, thereby to permit a variance in the pressure conditions under which said valveopehs.

The combination-described in claim 1, wherein'the-engine-is providedwith a-governor and said governor'is onnectedby linkage to the said second valve, ionalternative operation by the engine governor of said second and'relief valves in response to engine speed "and load.

4. The combination described in claim 1, wherein manual meansareadditionall'y provided to operatesaid-reliefand second valves as described.

5.--In an internal combustion engine super charged-byan-exhaust gas turbine driven blower and-cyan independently driven auxiliary blower, said engine-having an air intake chamber for the engine cylinders-a-conduit from the outlet of-said'turbine driven-blower to said chamber, saidauxiliary blower having-an air intake and a first air supply line extending from its outlet to said chainberand asecond air supply line from-itssaidoutlet'to the entrance to the turbine driventtblower, an arrangement for preventing surging in the auxiliary blower, said arrange ment comprising a valve in said first air line, said valve "being closedin response to the creation-of'a predetermined air pressure condition in the chamber as compared with the air pressure condition-in said-first air line, a relief valve between the au-xiliaryblower outlet and the atmosphere, said relief valve being connected with said .valve in thefirst ai r-linetoope'n and close simultaneously with the lastsaid valve, whereby when both -said-valves are closed the air output of-the auxiliary blower is directed through the second airline to the intake of the exhaust gas turbine driven blowenand when both said valves are opened, ah' fromthe outlet side'oi the auxiliary blower is permitted to flow at 'a predetermined rate back to the air'in'take of the auxiliary blower. thereby to prevent surging 'of the last ABFRED BiicHI.

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